Linkage between muscle and bone: common catabolic signals resulting in osteoporosis and sarcopenia.

PURPOSE OF REVIEW: This review summarizes the recent articles and perspectives about the linkage between muscle and bone. Moreover, it focuses on common, clinically important signals affecting both muscle and bone.

RECENT FINDINGS: The clinical significance of sarcopenia has recently been highlighted, and muscle mass and muscle strength affect osteoporosis differently. The link between muscle and bone is also important from the viewpoint of exercise therapy. The clinical evaluation of vitamin D insufficiency has been developed, and vitamin D action is important for both muscle and bone. Although several studies have suggested that there are some interactions between muscle tissues and bone, we found a novel local regulator that might induce osteoblast differentiation of myoblasts. Moreover, several factors were proposed as muscle-derived soluble factors that induce bone anabolic action. There have been identified linkages from bone to muscle, such as osteocyte-producing or bone marrow mesenchymal cell-producing factors affecting muscle.

SUMMARY: The links between muscle and bone are not fully understood at the present time. However, the development of research on the interactions between muscle and bone will be crucial for the development of novel drugs for sarcopenia and osteoporosis, as well as for the understanding of the physiological and pathological relationships of muscle and bone.